Passat fans keep. Coming on

[Mickpeace]

Hi just become a member to see if any one can shed any light ? Bought a passat 2.0 diesel 2011 new shape, temp was no reading 90 so I fitted the common temp sender, then I noticed the fans coming on even when cold, so I fitted a complete new thermostat and housing from vw, no runs on 90 but the fans come on sometimes even when not up to temp ? Does not use water, or and pressurising what so ever, ? Does the fuel sensor have any control of the fans ? Only thing I haven't swapped, ? Please advice gratefully..